Hardcode version string in src/raven.js (fixes GH-465)

[benvinegar]

Note src/raven.js specifies 2.0.0 because this is the current value of version in package.json on master.

When I cherry-pick this into stable/2.0.x, I will update the version string.

---

Grunt output when attempting to run grunt dist or grunt build when version mismatches:

➜  raven-js git:(master) ✗ grunt dist
Running "clean:0" (clean) task
>> 1 path cleaned.

Running "gitinfo" task

Running "version" task
Warning: Mismatched version in src/raven.js: 2.1.0 (should be 2.0.0) Use --force to continue.

Aborted due to warnings.

➜  raven-js git:(master) ✗ grunt build
Running "clean:0" (clean) task
>> 0 paths cleaned.

Running "gitinfo" task

Hardcode version string in src/raven.js (fixes GH-465)
Running "version" task
Warning: Mismatched version in src/raven.js: 2.1.0 (should be 2.0.0) Use --force to continue.

Aborted due to warnings.

[mattrobenolt]

Shitty, but the assertion makes it more palatable. 👍